Why 1,000 mg of Vitamin C Isn't Ten Times Better Than 100 mg
Vitamin C is the supplement most people buy on autopilot. A thousand milligrams has become the default — not because anything in the research points to that number, but because it is a round figure that looks generous on a label and costs a manufacturer very little to deliver. The biology underneath that number is more interesting, and once you understand it you will probably change how you take vitamin C, if not whether.
Absorption doesn't scale — it saturates
Most people assume that swallowing ten times the vitamin C means absorbing ten times as much. It does not, and the reason is structural rather than incidental.
Vitamin C is absorbed through specific transporters in the intestinal wall, and transporters are a finite resource. At low intakes they operate efficiently and take up the large majority of what arrives. As the dose climbs, they begin to saturate — the machinery is running at capacity and simply cannot process more per unit of time. The proportion absorbed falls, and it falls steeply.
The consequence is counterintuitive and worth stating plainly: as you increase a single dose, the fraction you absorb goes down. Past a certain point you are adding milligrams to the capsule and adding very little to your bloodstream. Your kidneys handle the rest, because vitamin C is water-soluble and excess is efficiently excreted rather than stored.
This is the honest basis for the old joke about expensive urine. It isn't that vitamin C doesn't matter — it is essential, and a genuine shortfall is a real problem. It's that the tenth multiple of a dose does very little the first didn't.
Splitting beats megadosing
If saturation is the constraint, the solution follows immediately: give the transporters time.
Two smaller doses taken at different points in the day will deliver more absorbed vitamin C than the same total swallowed at once, because each dose meets a transport system that has reset. Three modest doses beat two. This is one of the few places in the supplement world where a genuinely free change — the timing, not the product — outperforms buying something better.
It also explains why a 250 mg product taken twice daily is not the weaker cousin of a 1,000 mg once-daily capsule. In terms of what actually reaches your system, it may well be the stronger one.
Your gut will tell you when you've gone too far
Unabsorbed vitamin C doesn't vanish politely. It stays in the intestine, where it draws in water — the same osmotic effect that makes poorly absorbed magnesium a laxative.
The result is that high single doses cause loose stools and cramping in a lot of people, and the threshold varies widely between individuals. If a vitamin C habit has ever produced an unwelcome half hour and you blamed something you ate, the dose is worth reconsidering. The digestive signal is a fairly direct readout that you have passed the point where your body could take it up.
The forms, and which differences are real
Vitamin C comes in more variants than most nutrients, and the differences are smaller than the marketing suggests.
Ascorbic acid is plain vitamin C. It is what the overwhelming majority of the research used, it is well absorbed, and it is inexpensive. It is also the most acidic, which is the only real knock against it.
Buffered forms — sodium ascorbate, calcium ascorbate, magnesium ascorbate — pair ascorbic acid with a mineral to reduce the acidity. They are a genuine comfort improvement for people with sensitive stomachs. Worth knowing: buffered forms deliver that mineral too, which is a small consideration if you are already taking calcium or watching sodium.
Liposomal vitamin C encapsulates it in phospholipids with the aim of bypassing the transporter bottleneck. The mechanism is plausible and there is supporting research, but the category is inconsistent — "liposomal" is not a regulated term and product quality varies enormously. It also costs considerably more.
Ascorbyl palmitate is a fat-soluble derivative, mostly used as an antioxidant preservative rather than as a meaningful way to raise vitamin C status.
For most people, most of the time, plain ascorbic acid at a sensible dose taken twice a day is the rational choice, and the money saved on exotic forms is better spent on the timing habit that actually moves the needle.
The pairing worth knowing about
Vitamin C markedly improves the absorption of non-haem iron — the form of iron found in plants and in iron supplements. It reduces iron to a more absorbable state and helps keep it from binding to the compounds in food that would otherwise block it.
That makes vitamin C genuinely useful as a partner rather than only as a standalone. If you take an iron supplement, or you rely on plant sources for iron, taking vitamin C alongside is one of the highest-return, lowest-effort habits available. It costs nothing and meaningfully changes how much iron you get from the same meal or the same capsule.
Food first, still
It's worth saying that vitamin C is one of the easier nutrients to get from food, and the food sources bring more than the isolated nutrient. Peppers, citrus, kiwi, broccoli, strawberries and tomatoes all carry meaningful amounts alongside fibre and a range of other compounds a capsule doesn't replicate.
Vitamin C is also heat-sensitive and water-soluble, so prolonged boiling leaches and degrades a good share of it — which is a mild argument for eating some of these raw or lightly cooked rather than an argument for supplementing.
How to buy it sensibly
Check the amount per serving and be suspicious rather than impressed by very large numbers, because absorption efficiency drops as the dose rises. Decide whether you'll actually split it — if you will, a smaller-dose product is the better buy. Choose buffered only if plain ascorbic acid bothers your stomach, since it is otherwise an unnecessary premium. Treat liposomal as an optional upgrade rather than a requirement. And if you take iron, pair the two deliberately.
How we approach it
Our vitamin C states its form and amount plainly, with no proprietary blend obscuring the dose, and every batch is tested by an independent lab with the certificate for your lot published on the product page.
The broader point is the one worth carrying to the rest of the shelf. With vitamin C, the biggest number on the front of the bottle is not the most effective product — it's the easiest thing for a manufacturer to print. What your body actually receives is decided by absorption and by how you space it, and neither of those is something a label can shout about.
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.